# Human Calculator

November 29th, 2018 at 9:04:22 PM permalink | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

Pacomartin Member since: Oct 24, 2012 Threads: 881 Posts: 10537 | Below is a table of perfect cubes from 1 to a million. If someone gives you one of these numbers at random, can you calculate the cube root in your head?
For example, what is the cube root of 681,472 ? You wouldn't have the table in front of you so you can't find the position of the number in the table Actually if you can do this you would be sort of a human mini calculator, still far below Shakuntla Devi , a poor woman from India. Memorize this table
The first digit of the square root can easily be calculated by looking at the up to 3 digit number before the comma (if any exists)
Look at final digit in table memorized in step 1
Now try it again. What is the cube root of 148,877 ? What have you got to lose? |

November 30th, 2018 at 3:12:57 AM permalink | |

odiousgambit Member since: Oct 28, 2012 Threads: 97 Posts: 2431 | to solve the 23rd root, she would have been presented with : 916748676920039158098660927585380162483106680144308622407126516427934657040867096593279205767480806790022783016354924852380335745316935111903596577547340075681688305620821016129132845564805780158806771 she was better than my online calculator, which uses logarithms I assume. It came up with 546372890.9999996 as the answer , assuming that the above number is what was given to her Holy cow!* *no kidding, it just occurred to me that to say 'holy cow' might be very offensive to such a person, if she is Hindu. Is it possible that I summoned that up unconsciously? sorry for hijacking but I just had to ponder that Mustard:You like Kipling, Miss Scarlet? Sure, I'll eat anything [from movie] |

November 30th, 2018 at 6:12:28 AM permalink | |

Pacomartin Member since: Oct 24, 2012 Threads: 881 Posts: 10537 |
Yes, all calculators use logarithms to base 2. In 1988 Shakuntala did the cube root of 95,443,993 in 2 seconds. She died in 2013 and received a Google Doodle. 450 91,125,000 451 91,733,851 452 92,345,408 453 92,959,677 454 93,576,664 455 94,196,375 456 94,818,816 457 95,443,993 ---------------------- 458 96,071,912 459 96,702,579 It is actually possible for a normal person to do the cube roots of perfect cubes up to a million in 2 seconds, although you may want to draw it out as party trick. |